Over the past few decades, the technology and requirements for wire coiling have changed significantly, from low volume coiling of relatively coarse wire using high power machines, usually with gear reduction mechanism, to coiling of ultrafine wire at high speeds and high output rates. This significant change was caused at least partially by efforts to save energy by using smaller resistance coils in heating elements, and at least partially due to sophistication of instrumentation and the like using coils. In coiling such fine wire, control of the coiling pressure is important, and in fact should be independent of drive pressure. The front forming rolls should apply balanced coiling pressure to both sides of the coil being formed around the forming arbor. Moreover, this should remain true even if the diameter of the forming rolls and/or drive rolls become worn or are modified slightly by regrinding of these rolls to accommodate for wear.
For practical reasons, the coiling power needs to be transferred from the rear of the coiling machine to the front where the coil is being formed. In times past, the power takeoff rolls at the rear were of very substantial diameter, e.g. at least four inches, and later greater than six inches in diameter, driving much smaller forming rolls at the front arbor, see for example the relationship between the roll diameters in my 1963 U.S. Pat. No. 3,082,810. Many years later, I developed the coiler in my 1981 U.S. Pat. No. 4,258,561 to coil very fine wire. Unfortunately, it was subsequently learned that the power pickup in that latter apparatus caused it to be extremely limited in the wire size it would accommodate. When coiling equipment is used on a production basis, regrinding of the power takeoff rolls and the coiling or forming rolls is a constant maintenance necessity, so that the usefulness of the apparatus in this '561 patent was considered too limited.
I have determined that the industry is now in need of a high speed production coiler for fine wire sizes, capable of day-in, day-out high speed production, with full synchronization from the rear arbor to the coil being formed. Such production requirements necessitate periodic regrinding of the resilient power rolls as well as the steel coiling or forming rings or rolls to accommodate for wear, causing diametral differences which the machine must automatically accommodate without loss of synchronization. Yet the machine should be simple and uncomplicated in construction, free of gear or belt reduction drive mechanisms from the rear rolls to the front rolls.